Wimper in German translates to “Eyelash”. This contact switch is made from conducive thread stitched intoto create “lashes” that hover over a band of silverized nylon stretch . Contact between a lash and the band closes the switch.
In exploring different methods for detecting movement/passing of the tiniest/lightest of creates this is simple contact switch made from strands of super thinand a surface of conductive fabric. The thread is stitched into a strip of neoprene, and stretching the neoprene allows you to adjust the spacing and height of the threads. A band of stretch conductive fabric is placed just close enough to the lashes of conductive thread so that there will be no electrical contact unless an animal crawls up onto/over one of the lashes and causes it to move down against the conductive fabric. Analog sensing of this sensor might also allow to detect varying amounts of motion, or size/weight of insects….
Andrew Quitmeyer wrote up a beautiful tutorial on a larger class of experiments we did building sensors to detect ants. Step 8 of the following Instructable describes the “Wimper Switch”:
This sensor was built with the intention of detecting ants crossing over it as they travel up and down the trunk or branch of a tree. A first prototype was built during the Hacking the Wild expedition into the jungle of southern Madagascar. Unfortunately the stainless steel thread we had with was too stiff for the weight of the ants to bend. Since arriving back in Europe I’ve prototyped a version with the much softer silver plated nylon conductive thread 117/17 2ply by Shieldex. But I have not been able to test it with any ants yet because here in Austria the ground is still covered in snow:-)
Some variations (using stainless steel thread):
Lashes over conductive fabric band:
Close-up of some ants crossing but not heavy enough to have effect:
Loop lashes instead of hair-like lashes:
Sperate rows of loop lashes that contact each other:
Some variations (using silver plated nylon conductive thread 117/17 2ply by Shieldex):
Electronic symbol for an ant-triggered switch:
Inspiration for this switch/sensor came from observing ants crawling over moss and how the ants were heavy enough to make the moss bend.